Ruse Spells

Spells with the ruse descriptor are easily mistaken for other spells and are intended to confuse even onlookers trained in Spellcraft or Knowledge (arcana).
Attempts to identify a ruse spell by its effects, its aura, its components, or other attributes with a skill check treat the spell as though it were a different spell, as indicated in the spell’s description. The one attempting the check can correctly identify the spell only by exceeding the DC by 10.
The false spell is typically a level lower than the ruse spell, so skill checks use the DC for the lower-level spell. Even Detect Magic and most similar spells don’t prevent the caster from being fooled by a ruse spell.
Analyze Dweomer, Arcane Sight, Greater, and similar spells of the same or higher spell level that automatically identify spells reveal a ruse spell for what it is.
Ruse spells that mimic harmless spells still list harmless on their saving throw or spell resistance lines; a creature that knows or suspects the true nature of the spell typically chooses to attempt the save.